1. Technical Field
The present invention relates to compounds effective as leukotriene B.sub.4 antagonists.
More particularly, this invention relates to leukotriene B.sub.4 antagonists, to processes for producing them and to pharmaceutical compositions containing at least one of those leukotriene B.sub.4 antagonists, which have excellent anti-leukotriene B.sub.4 activity and are useful as an anti-allergic agent or an anti-inflammatory agent.
2. Prior Art
In 1979 B. Sammuelsson reported the isolation and biological effects of leukotrienes (B. Sammuelsson et al. (1980): Advances in Prostaglandin and Thromboxane Research, Vol. 6, edited by B. Sammuelsson, R. Ramwell, and R. Paaletti, P. I. Raven Press, New York).
Since then, a tremendous amount of research in the synthetic organic chemistry and pharmacology of leukotriene A.sub.4, B.sub.4, C.sub.4, D.sub.4, etc. has been performed.
Leukotrienes induce an increase in capillary permeability and cause smooth muscle contraction. Leukotriene B.sub.4, one of leukotrienes which is shown below, has different pharmacological properties from the others. It is chemotactic for macrophages and neutrophils at concentrations of .about.1 ng/ml (greater than any other known lipid chemotactic factor). It is detected in the synovia of patients with rheumatoid arthritis or gouty arthritis, and in the sputum of obstructive airways diseases which suggest that it is a primary mediator of inflammatory and allergic states. ##STR2##
In recent research some compounds having an antagonism on LTB.sub.4 have been reported. For example, ##STR3##